The present invention relates to a metal U-channel shaped element for reinforcing concrete floors, and in particular a self-supporting element suitable for being embedded in a concrete casting so as to form the reinforcement of the floor joists on which light material filling blocks, such as tiles, are made to rest in the technique of building floors made of concrete and blocks.
It is known that at present in the building technique trestleworks of floors, vaults and the like are made by using prefabricated reinforced concrete joists or by building such joists where required by embedding a suitable metal reinforcing structure in a concrete casting.
The utilization of prefabricated joists shows the drawback that certain given standard sizes are needed with the consequence that the possible degrees of freedom are reduced both in planning and in building. Furthermore, in this case, the user cannot reliably check the pattern, the steadiness and in general all the features of the reinforcement.
On the other hand, the joists formed in an erecting yard from time to time, show well known inconveniences, such as of requiring time consuming hand-made iron or wood structural works for arranging reinforcing rods and installing the necessary boxings. Such works involve costly labor, in addition to obvious environmental difficulties.
It is true that the same Applicant has designed and produced a pre-formed self-supporting metal trestle, adapted to be manufactured in a factory by means of industrial methods and apparatuses and hence to be supplied into the building yards at the desired lengths in order to be embedded in a concrete casting with no need of boxing or molds. Such metal trestle, being the object of the U.S. Pat. No. 3,828,505, requires however for its manufacturing plants and machines of high cost and complexity, having a trestle production per hour which does not fulfill the building demand and what would be desirable in order to conveniently utilize the production plants from the economical point of view.